Sunday, October 26, 2014

Continued modelling of the Turin Shroud image: two alternative options for flour-assisted thermal-imprinting - both feasible, but neither without its difficulties

Models are to be used, not to be believed"

Henry Theil (economist)

Here's a photographic record of the experiments conducted this Sunday morning in my humble home laboratory - or what my wife continues to refer to tediously as "her kitchen".

See the postings immediately preceding this one for how we come to be where we're at this present point in time. It's been a long journey (getting on now for 3 years - see this blogger's first Shroud posting).

Here we go again. This is the Mode 1 option (see previous posting) in which the white plain flour is sprinkled  onto the linen, then lightly brushed in. The brass bas-relief  template is to be heated and pressed into the flour-coated linen.

End-result: a very satisfactory thermal imprint, aka scorch. Note the lack of sharp definition,, a bonus of sorts maybe.

Close-up of Mode 1 'fuzzy' image. Improved model for the TS, given that some say scorch imprints are too sharp and well-defined?

First step in deploying the alternative Mode 2 option. Coat the template with white flour, having first applied a thin smear of vegetable oil

Press the coated template into linen

After impression. The flour imprint on linen not yet visible in this pic until next stage (roasting).

First sign of an image appearing on roasting

Image now becoming more apparent, even if not immediately recognizable as a horse brass.

One can now see the outlines of the horse brass, even if it's not clear there's a crowned head of state (Queen Elizabeth II's dad, George thethethe VIth).

The monarch's head is still not obvious. Maybe the technology needs to be refined.

Time to run  a control - oil without flour.

Close up of oil-only imprint.

Even oil alone gives a vague image of sorts - but it's nowhere near as sharp as a flour image, making a  super-fuzzy flour/OIL imprint even MORE credible, given the ghostly character of the TS image.

Preliminary conclusions:  

Mode 1 imprinting with a hot template onto flour-coated linen is by far and away the easier of the two options, at least on a small-scale. What's more, the image is much fuzzier, and dare one say more Shroud-like, than comparable images on plain untreated linen. Need one look further? Might flour-coating and hot template imprinting have been the simple technology that was employed some 650 years ago? Is the TS image primarily a Maillard product, the result of chemical reaction between reducing sugars and protein - not a simpler thermal decomposition product of pyrolysed linen carbohydrates requiring no amino-nitrogen (-NH2) whether from proteins or post mortem decay?

But simpler technology in what sense? Merely because the image-making process can be targeted to particular areas of linen by means of a heated template? It's one thing to heat  horse brass to temperatures between 220 and 250 degrees C, and  manoeuvre  into position,  another to do the same with a life-sized effigy.

So might it have been Mode 2 technology that was chosen?

It has clear advantages over Mode 1, in that ANYTHING with 3D properties can in principle be imprinted, not having to be heated. That might be bas relief templates and/or fully 3D statues.  It may even conceivably have been a person, living or dead.  All that was needed was a coating of white flour (or a comparable dry powdered substance providing reducing sugar and amino groups), probably with a binder material to ensure adhesion and even coating (the vegetable oil in the present modelling, but other options exist).

But there's a tricky step in the procedure - namely the final roasting of the flour-imprinted linen that has to convert the coating to tan-coloured melanoidins (Maillard reaction products) without too much discoloration of the linen. It can be done in  principle, on a small scale laboratory basis, given the exceptional chemical and thermal stability of cellulose, by far and away the major component of linen fibres, relative to the the starch, proteins, lipids, non-starch polysaccharides etc of white wheaten flour. But an entire burial shroud?

There's a great deal to think about right now. Best maybe to stop here and post the experimental results. Perhaps others can see things I have missed that might offer a way forward through this thicket of new possibilities, each with its own unique potential (and accompanying difficulties).

To those who claim I select and/or manipulate experimental data I say this. Go boil your heads (old English expression of endearment).

Monday 27 October

By way of postscript, I must add that my thinking is changing by the minute as a result of re-adjusting to the idea of the TS body image being heterogeneous, as shown by its two-tone character.

I'd previously suggested that the rosy regions represented the highest points on the 3D relief of a template. (Let's not concern ourselves too much right now as to the precise nature of the template). But the nose is not rose coloured like the cheeks, chin, chest and shoulder blades. Why not, given its prominence where facial anatomy is concerned?

 What's more,  there's poor correspondence between a  map of rosy colour and that of the same Halta image in ImageJ in Thermal LUT mode,  using the latter as a probe of image density, and accordingly serving provisionally as an indication of presumed 3D relief (used cautiously). I may add some graphics here later to document those statements.

One could argue, of course, as Luigi Garlaschelli has done, that a bas relief would need to have been used for the face to achieve imprinting without excessive lateral distortion, and that's a view with which I have long concurred.  But there's another possibility, prompted by what I see on so many flour imprints, in either of the two modes, namely that the regions of rosy colour are where there has been greater thickness of hypothetical flour (Mode 1) or greater adhesion of that same flour to the template (Mode 2).

Update: 17:45  October 27th

There's a distinctly bad smell coming from the world of shroudology right now, and has been ever since that pseudo-conference in St.Louis dumped still more pseudo-science on us all, lauded through the usual channels.

Am now taking a break from shroudology for a while.

I'll still be researching my Maillard-assisted  imaging with the flour, and be thinking through the wealth of new options it opens up, maybe drafting some new posts. But  I shan't be reporting, not any time soon, much as I would like to. Time to head for the hills - the air's cleaner there.

Reminder:I have consistently stated from the start of this project that my objectives are limited. There is no aim or ambition to re-create the TS image, as we sceptics constantly find ourselves challenged to do so. Whilst having the greatest admiration for those who have attempted that, and who indeed, notably Garlaschelli certainly exceeded my own expectations of what can be achieved by 3D ->2D imprinting, my own goal is more modest. That is to respond to the claim that the TS image is uniquely subtle as regards superficiality and microscopic properties. In other words, it is primarily the scientific principles that interest me. Was a supernatural event really required, as claimed by those ENEA self-styled 'scientists' (?). Had they really done a long thorough job in excluding conventional science as they claimed three years ago in their press releases?

I have arrived a modified scorch hypothesis that sees a role for an adjuct, namely a binary mix of Maillard reaction precursors, one that serves to sensitize linen to heat. Straightaway one can  easily model TS-like images that have that peculiar fuzziness to them. It's only a first step, but an important one, given the focus some have placed on image definition.

I have informed folk of the scientific basis of this new approach. White flour was arrive at entirely via a scientific route, one that started with an investigation of the invisible ink effect with lemon juice, and then linked that as others have done to  Maillard chemistry (not acid etching). That train of thought then converged with a separate one based on image analysis*, using especially the Halta Definizioni image on the BBC site.

* To which a technical appendix on my approach and methodology was placed yesterday on the second of two postings.

 No Dan Porter, I am not a small boy playing with flour, and your continued attempts to infantilize do you no credit whatsoever. Nor does your attempt to block free speech. Nor does your tolerance of trolls on that site of yours who specialize in making character attacks.

Go boil your head, Dan Porter. I'm heartily sick of you and your tedious popgun attacks, 

  Wednesday 29 October

I have spotted Dan Porter's response to my comment above. An apology is not to be lightly dismissed, and to do so would be ungracious. Nevertheless, I consider there are serious issues that remain unresolved regarding the instant reporting of ongoing research, and the kind of comments that appear from certain individuals, albeit a minority, who collectively might be called a mean-spirited knocking brigade. 

One suspects they take their cue from the slightest hint from a blogmeister that the new research is in his view not quite up-to-scratch. It's those instant judgements that encourage the trolling element, and which also probably inhibit those who might wish to initiate and/or engage in a freer less-partisan debate that does not instantly pre-judge. 

I shall say no more for now, if only because I'm trying in spite of everything to stay focused on the task in hand, which is to decide if the key to the peculiar TS image was the use of a powder barrier of some kind between a heated template and linen, and if so, whether that barrier substance was chemically prone itself to scorching (e.g. white flour),  or was chemically inert, acting merely as a thermal barrier to over-rapid heat conduction (powdered chalk?).

I'm running some further tests in an attempt to get a handle on this question, but don't expect instant results, and don't expect future findings to be instantly reported, if all that does is to elicit instant knee-jerk put-downs.

 After some 3 years of writing real-time research reports, this blogger/experimentalist is now a sadder but wiser man where the internet is concerned. Trolls, and those who tolerate them, are the curse of web-based information-sharing.


"But I don’t see how with 3D statues, bodies and whatnot, we are not facing the well-understood contact-wrap-around problem. What am I missing?"

Luigi  Garlaschelli had something to say on that score , and I'll try and find his exact words and insert them here later. For now, there are two main points that need to be made. First the TS image does not look like a photo of a 3D person in which one views the sides of the face or torso, limbs etc at an increasingly oblique angle. The TS image does not have sides, receding or otherwise.  It's essentially bas-relief in that respect, like the head or emblem on a coin, with just enough 3D relief to create a realistic effect, and then only after uploading to 3D-rendering software (ImageJ etc).

Secondly, the idea that imprinting off a fully 3D object or person must always produce a grotesque image with lateral distortion simply isn't true. That is only the case if one uses, say,  paint as one's imprinting medium, and makes a conscious effort to press the fabric around the sides to ensure image capture through a wide arc of circle.

But taking a thermal imprint is not the same as creating one in paint if the heated template is pressed down into linen. Why not? First, considerable force is needed to get appreciable penetration into the linen if there's an underlay (say a damp cloth) offering resistance to penetration. So the end result may look as if it had been taken from a bas-relief - because much of the 'side relief' has escaped being imprinted.

There's another factor. Even if the linen did make contact with the 'side relief' it may receive little heat because of the angle of presentation. Thermal imprinting requires heat transfer which in turns requires contact pressure acting at or close to the geometrical normal. Pressure is less important if one is using a "sticky" substance like paint on which so much of the "lateral distortion" notion appears to be based.

Here are thermal imprints obtained by pressing a heated brass crucifix into linen, placed over a damp underlay, either standard  conditions (no flour) or the new system (a thin layer of flour brushed over the surface), Ignore the water stains coming up from the underlay - except that they serve as a marker for impact pressure

Where's the lateral distortion in either picture? If it's there, it's very slight.

 Those two imprintings have since been thoroughly rinsed in warm water, and are presently hanging out to dry, to compare the water-resistance of the two images.

While waiting for that result, here are the above images after 3D rendering (ImageJ).

 Note the TS-like 3D appearance of an imprint off a 3D 'subject'. So why all the current preoccupation with the notion of the TS image having been "painted"?  When did we last see a painting with no 3D history respond so magniificently to 3D-rendering? In any case, where's the evidence for a classical artists' pigment?  Walter McCrone pursued an iron oxide will o' the wisp,  and ended up in a microscopist's mire of his own making.  STURP found none, and instead found a reflectance spectrum that matched that of "dehydrated, oxidised, conjugated (don't-call-it-a-scorch) linen carbohydrate. 

The easiest way to create a negative image, if that was the intention, maybe to simulate a Veil of Veronica type 'sweat imprint',  is to imprint off a shallow bas relief template. All one has then to do is to choose one's imprinting medium. Pigment? Chemical etching of linen? Simple contact scorching? Invisible ink (lemon juice or milk effect)?  The possibilities are endless. I've just added another to the list of candidates - plain white flour. What's more, it's been tested  and so far not been found wanting. But these are early days. Maybe not as early as 30 AD, but mid-1300s looks a better bet. I raise my hat to the medieval artisan who pulled off the greatest marketing coup in all of history against some keen competition (don't ask).

And here are those same two images after repeated washing and wringing out in warm water:

 Both images have survived having the excess unreacted flour washed out.
It's not that I imagined that water-resistance was a prerequisite for the TS image itself (while recognizing it has been exposed to water). It was more a case of wanting to be sure that there was not a layer of unreacted starch between image and linen that might have degraded and/or lifted off over the centuries, taking the image with it. The water test suggests that the image is in close contact with and firmly bonded to the linen.

Here's the same picture (immediately above) after 3D rendering.

Might it be said that the flour image is the more subtle of the two, if only that more of the heat-induced pigment (Maillard) has been washed out?

There are some interesting correspondences too between the regions of highest image density and those on the Halta Definizione image (BBC site) after image-enhancement, notably the head and shoulder blades. That may be pure coincidence, needless to say. Again, it has to be repeated, where's the lateral distortion?

 Addendum Thursday 30 October

Earlier I expressed surprise at being unable to see an 'elevated' nose in a colour-coded 3D rendering of the Halta Definizione image,  i.e. in ImageJ's Thermal LookUp Table mode. That was a clear embarrasment where one's model of imprinting off a 3D template is concerned, though there's a possible 'out',  admittedly not terrible convincing, by supposing a very shallow bas relief was used with a pancake-like nose.

No need for consternation and alarm. I've just run through the Thermal LUT imaging again, upping the min value control (lower right) in small increments.

All settings the same except the "min" value, lower right hand corner, which was gradually increased from left to right to stretch/amplify the vertical relief (see colour-coding bars). All were done on the "as is" Halta image off the BBC site.

 The nose IS there showing high relief, but it only shows well over a fairly narrow range of min values (60-73%) and even then is somewhat blade-like at most settings. Here's a close up of the third graphic in the above series which arguably shows the nose to best advantage as being at least comparable to other high-relief features.

Yes, the nose IS quite definitely there. How did I manage to miss it first time round?

Phew. For one moment I thought we were in trouble (especially in view of all the current Shroudie chatter about the image having been painted on, the pigment having since conveniently flaked off - every last bit of it - to leave just a faint cast or shadow of its former self. Yeah, right).

I personally prefer STURP's interpretation (my bolding):

No pigments, paints, dyes or stains have been found on the fibrils. X-ray, fluorescence and microchemistry on the fibrils preclude the possibility of paint being used as a method for creating the image. Ultra Violet and infrared evaluation confirm these studies. Computer image enhancement and analysis by a device known as a VP-8 image analyzer show that the image has unique, three-dimensional information encoded in it. 

                                       (Chunk of text omitted here in interests of brevity)

The scientific consensus is that the image was produced by something which resulted in oxidation, dehydration and conjugation of the polysaccharide structure of the microfibrils of the linen itself. Such changes can be duplicated in the laboratory by certain chemical and physical processes. A similar type of change in linen can be obtained by sulfuric acid or heat. However, there are no chemical or physical methods known which can account for the totality of the image, nor can any combination of physical, chemical, biological or medical circumstances explain the image adequately.

                                                        STURP 1981

Pity STURP and others missed the two-tone image.  Had they not done so the possibility could have been entertained of there being image not only on the linen fibres per se, but on an additional impurity coating, maybe Rogers' starch and saponins (though I doubt it) or alternatively on some additional material capable of producing its own red-brown coloration, one for which my plain white flour serves provisionally as a model. See the quotation at the top of this posting.

Thursday 10:36

Oops. Have just realized the source of my error as regards interpreting the two-tone image.

I interpreted the rose-coloured regions as being those with the highest relief (chin, cheekbones, brow ridge etc on the face, and the chest, shoulder blades etc on the frontal and dorsal sides). That's why I was at a loss to  fathom why the nose was not also rose-coloured, but we know it's high relief.

Scales have suddenly fallen from eyes. It's NOT (just) relief that is responsible for the colour. It's something else. But what?

Might the flour model be giving us a clue?  It's not just the elevation (necessary but not sufficient). It's the FLATNESS of those areas. The nose does not work because while it's elevated it's not flat.

So why should an elevated flat region result in a different tone? Maybe an added powder (like my white flour model) sticks to it better.

Ring any bells? Luigi Garlaschelli used powder 'frottage'. Interestingly the powder was artist's ochre, i.e. red iron oxide, Fe2O3.  Now I'm sure if the rose -coloured regions above were iron oxide, then we would know about it, given the focus that Walter McCrone had on iron oxide too in trying to prove the TS image had been painted on.

So where does that leave us? My initial hypothesis still stands - that we are looking not only at scorched linen fibres but an additional Maillard product from a thermal interaction between a reducing sugar and protein (or some other source of amino groups). But we now have to consider other possibilities that do not necessarily involve any chemical reaction at all, but simple adhesion of a fine powder to elevated flat regions, maybe with some thermal bonding too to explain why they don't all quickly drop off.

Thursday 13:20

So what about the real thing - the Turin Shroud?  Does it show any visual evidence, under the mciroscope, of having been coated with a powder of some kind?

Unfortunately i don't have access to an archive of photomicrographs, and the only person I know who does is Thibault (aka Thunderbolt ;-) Heimburger. He included some Mark Evans close-ups of image areas in the first of his 'anti-scorch' pdfs (there was a second selection too that came a while later which I am trying to track down).

Here's just one I found showing precisely what I predicted (though whether that's a fluke or not remains to be seen).

Look carefully at the regions o highest image density inside the yellow rectangles. See anything?
Here's the same with new settings (-11,100,1)

Am I not correct in thinking that there are dark specks associated with the tan-coloured areas, which are unlikely to be artefactual (chance deposits of dust etc) given they are absent for all intents and purposes in the less-strongly coloured non-image areas?

Flour particles, toasted?

I really must find those other Evans pictures, labelled according to anatomical region (nose etc) as I recall.

13:50  Have located the link to the pdf, which can be found on this shroudstory posting from about a year ago.

13:55: Yup, everywhere you look, you see those black specks on the image-bearing threads. They don't seem to be anything like as well represented on adjacent paler threads.

It's going to take a while to get all those images captured and cropped. I'll be adding them here on the end, having made a decision to stop putting up new postings (mentioned earlier) and concentrating instead on reinforcing the ones I've already posted with technical appendices etc etc.It's sufficient now that folk know my preferred model(s) and the general direction of my research. There is no need any longer to spoon-feed on a daily basis (and it takes the pressure off me not to feel I have to post - and then have to endure the guaranteed sneers and sniping from the anti-anti-authenticity brigade. Go boil your heads, you anti-anti-authenticity brigade.


Click to ENLARGE. Look for dark specks.

Click to ENLARGE. Keep looking

Click to ENLARGE etc

Click to ENLARGE etc

and now. last but one, here's one kind of control, which is not an image region but a scorched region from the 1532 fire.

Is it my imagination, or are we seeing far fewer appearances of those dark specks?

Just one more. (I'm keeping the fly in the ointment till last).

OK. So who said anything about it being a perfect world (this being the only picture I can find for "Clear cloth", which sadly is not clear enough of dark specks for my liking). But at least one of  the particles  looks distinctly blue, so can hardly be a toasted flour particle. I would say the general impression is that of a relatively clear,field  something one cannot say for the image-bearing regions where the dark specks seem more prominent. But they will say I am biased won't they ( which of course I am) ? But at least I admit that, and do not pretend to approach science with total objectivity. How can one do so if attached to a particular working model? The important thing is to have that working model , to make its presence visible in one's Discussion, such that folk can recognize and discern one's bias. One cannot hope to eliminate bias in science. One has to be content with recognizing it and containing it.

Working hypothesis. There are (or were, before the 2002 conservation measures, including that unforgivable hoovering) a scattering of dark-coloured particles on the TS concentrated mainly in the image-bearing regions, with far fewer in non-image regions.

An analysis of those particles would show them to be a substance that has been rendered yellow or brown by thermal energy ("heat" in common parlance). A possible candidate might be white flour particles  - an intentional additive - one that  acquired colour via a Maillard reaction, thus contributing to the image-forming process and  hence its heterogeneity and complexity.


As ever, more and more work beckons. First, one will need to do microscopy on the flour-coated  imprinted linen to see what happens to the appearance of individual flour particles, and whether or not they match the specks one sees in the above Mark Evans pictures, at least in terms of size.

Then comes the difficult part: to track down such papers are available online from the Walter McCrone Microscopy Institute on the studies he did on sticky-tape samples supplied by Ray Rogers. I definitely recall seeing one summary that had a long long list of the different types of particle he had identified.

One wonders what he would have made of those dark specks we see above if indeed they were flour or some other 'food' type particle that had undergone a Maillard reaction. One imagines it would take some fairly sophisticated kind of spectrographic microscopy  to make a positive identification, but that is not my area, so there's a steep learning curve that will need to be climbed to make headway.

Friday 31 October

Here, right on cue, is the NY-based legal beagle John Klotz, leading member of what I termed the 'anti-anti-authenticity' brigade:

John Klotz
October 31, 2014 at 5:35 am
It wold be nice if before he comments that Colin acquaint himself with the breadth of of the STURP study. Dark spot anomalies were discovered among on the the foot and kneww. They have been subsequently analysed as limestone consistent with limestone found in Jerusalem.
I recall that Berry’s expertise and career involved analysis of issues related to nutrition? If so, I would suggest that he get his head out of his …oven.
It would be nice if Colin has a sense of humor but he will probably have a snit about my analogy.

Forgive me if I leave the "science" such as it is to another day. I do not engage with trolls. The proof that John Klotz is a troll, not that any is needed,  is the routine label he likes to stick on us - viz. "pseudo-skeptics". The suggestion is that anyone who attempts to argue that the TS is of medieval provenance is covertly pushing some kind of hidden agenda to do with religion or ideology (and yes, an attack on HIS religion, HIS ideology).

This retired biochemist (who has worked in many areas of health, disease and biomedicine, nutrition being just one) had a long-standing interest in the TS going back to the late 70s ("Silent Witness" etc). It was re-awakened by headlines that appeared in UK newspapers some 3 years ago, which incidentally prompted the very first posting on this site - the reporting of new experimental phenomenon that I called "thermostencilling". (December 2011)

 An example of a headline ("The Independent", Dec 2011) that really stuck in this scientific craw was
this one (there were many more in a similar vein)

Don't you just love the bit about ""after years or work trying to replicate the colouring of the shroud..."? Published where, one might ask? Or even just mentioned in passing at which of many shroudie congresses?

No John Klotz and fellow ideologues  It's now't whatsoever to do with philosophy or theology or cosmology or your own peculiar mish-mash of quantum something or other. It's purely to do with science and its unique modus operandi, shamelessly bypassed I might add by those publicity-hungry so-called scientists at ENEA. (In the UK we would have described them as technologists, not scientists, based at any rate on abstracts of their published output).

 Technologists should leave science to the scientists -  but that's by the way and a personal view needless to say. Lawyers too should not presume to know what this scientist has or has not read - but I'll tell John Klotz this for nothing.  I have forgotten more about the properties of calcium carbonate in its different crystalline forms than he will ever know.

October 31 19:40

Here are my future report dates.They will be short simple summaries describing simply what was done, and what if any (firm) conclusions were arrived at.

If there were no firm conclusions, a statement to that effect will precede the report.

Friday 14 November

Friday 28 November

Friday 12 December

Tuesday 23 December

Dates in New Year to be announced.

Righty ho folks. Time now for a quieter life. That's me signing off for 2 weeks.

Technical appendix

McDougalls Plain Flour:

Composition (per 100g)

Carbohydrate: 70.1 g
of which sugars: 1.4 g

Protein: 10.4g

Fat: 1.3g

of which saturates: 0.2g

Fibre: 3.2g

Sodium: trace

No information is given on the composition of the sugars, but I would expect them to be mainly glucose, maltose,  maltotriose etc, i.e. reducing sugars derived from starch amylolysis, rather than the non-reducing sucrose.

Friday, October 24, 2014

Modelling the Shroud of Turin image with a flour-assisted Maillard browning reaction.

This is simply to flag up the new direction my research has taken, prompted by the discovery that the Shroud image is in fact two-tone (see posting that immediately precedes this one). While speculative, it is possible that the image is a composite of an intense  orange-brown scorch on linen fibres per se, with a wider more diffuse image that represents something else, possibly a Maillard product on something that had been added to the linen as a surface coating.

Here are just three pictures, obtained today in my kitchen laboratory, that suggest my latest modification  of the contact scorch hypothesis developed over close on 3 years, based on image analysis, may prove fruitful. We shall see.

Care to guess what's happening here?. The linen is receiving heat from underneath. No, there's not a template in sight.
(Late note: it's a rotten lousy picture I know, but read on into the Technical Appendix for more taken in the same series, and you'll see why I chose one with too little rather than too much development).

Here's a clue. It's the template, a few minutes before the above picture was taken.

So what's that coating? Looks like flour. Might it be flour?

The image from that crucifix, obtained with a Maillard reaction that did NOT require pressing hot metal into linen, was a bit disappointing, but then it was the first trial of the new technology. A better result was obtained using a bas-relief metal template, i.e. a horse brass with King George VI.

Pity I chose to roast over a grid, but it's the principle that matters.

Notice the dusting on the horse brass. Yup, it's that flour again! It was preceded by a light smear of olive oil.

21:00. These findings did not come out of the blue. They followed on from those of the systematic testing of flour impregnation of linen, as yet unreported, the design for which was flagged up in the previous posting. Having quickly established  this morning that flour was indeed an agent for sensitizing linen to thermal 'scorching' via  the expected Maillard browning reactions, leaving untreated linen unaffected, there seemed little point in making a meal of the routine preliminaries - needed for sound science,it goes without saying,  but not conducive on a blog to holding one's readership, though rest assured those tests were done.

  Takeaway message: the initial hunch was confirmed, namely that flour does indeed contain all the ingredients for an in situ Maillard browning reaction:  flour dusted onto the surface fibres of linen should, and indeed does, act as a heat-sensitizing agent. The beauty of flour, needless to say,  being a finely particulate solid, is that it does not soak through as would a solution to the opposite side to give an image there as well, except possibly a ghost image due to migration of a few particles through the interstices of the weave. ( See "Shroud second face". Possible explanation?)


Slight change of plan: the original intention was to keep this as a reader-friendly 'short communication' and in fact end right here, with an assurance that the bulk of the supporting evidence would be along at a later date in some shape or form. But on reflection, separating off the teccie stuff is not an ideal solution in this cruel old blogosphere where uncharitable souls can and do accuse one of posting material that is 'light' or even 'empty'. (Reminder: I stated at the outset that my Shroud research would take the form of an account in real time of experimental activity, thought-processes, and, finally,  hard data and conclusions, but there would be no attempt - or pretence- at writing 'scientific papers' as if for conventional peer-review. My peers are anyone who logs onto my site(s), who may if they wish avail themselves of the Comments facility if they feel moved to do so. I leave it to scientists with laboratories at their disposal to decide which if any of my claims stand up to testing under more rigorous conditions than I can hope to deploy in a kitchen-laboratory.)

There's another solution that I'm minded to adopt, which is to pause after making the initial "short communication", and then add a technical appendix, making it clear that it does not need to be regarded as essential reading by those whose time is at a premium,  or who don't need  or wish to be burdened with the detail, being content perhaps to know that the detail was not skipped.

Yes. That's is what I shall do. Expect to see a Technical Appendix appear here later in the day that will be assembled in instalments. It will start with a description of the initial tests with flour that established that a standard  food ingredient in use for millennia containing both reducing sugar (free or potential) and amino groups (primarily as protein) might serve as an image-imprinting surface-coating that would or could acquire a scorch-like colour at a lower temperature than untreated linen. In other words, one was looking for a scorch via a Maillard browning reaction rather than simple pyrolysis. Having confirmed that prediction, there were then two quick trials, each taking less than an hour, of using flour as a imprinting agent, reminiscent perhaps of Luigi Garlaschelli's remarkable production of a TS-like image by what he termed 'powder frottage' using , among other things, artists' ochre (powdered red iron oxide) with a crucial baking step. The first used the 'KIng George VI' horse brass as a bas relief; the second, more ambitious, used a fully-3D brass crucifix (both these templates having been deployed and reported on previously).

Technical Appendix

Fig.1: Sprinkle plain white flour onto linen from a 'pepper pot' next to a straight edge. (Ignore the scorch imprints on the lower edge, which are from a previous experiment). The brush will be used to obtain an even layer.

Fig.2. Appearance after smoothing out the flour.  (Again, ignore those 3 scorches from the previous experiment)

Fig.3. Remove the straight edge. Now ready for the first imprinting, where a heated metal template will be applied so as to make contact with flour/non-flour zones simultaneously.


Fig.4. Heat up  metal templates (A is the one I have used for close on 3 years, B is a brand new one)


Fig.5. Success with the very first impressing, closest to the green tape.  There has been selective scorching of the flour - the linen being largely unaffected. Note there was only enough heat to get a single intense scorch. The Maillard reaction must be strongly endothermic (i.e. heat-abstracting) which is good in a practical sense (reducing the risk of too much heat penetrating into the deeper layers of the weave).
Fig 6. Final appearance after 4 pressings, each starting with a template straight off the cooker hob, and used  for obtaining  consecutively : 2 serial imprints (Exp 1), a further 2  after re-heating (Exp 2), a further 3 after reheating (Exp 3) and a further 3 after reheating (Exp 4), making 10 pressings in all from 4 heatings.

 Conclusion. The white flour performed exactly as predicted, making it possible to create a scorch imprint on linen at a lower temperature (undetermined) than is needed to scorch uncoated linen.  I would not expect to obtain the same result with pure starch, given that a source of amino (-NH2) groups are needed in addition for a Maillard reaction, but have not done a flour/starch comparison as yet. (May do so later).

 Late addition: 29 October : have done a quick test with corn starch (misleadingly called cornflour in the UK):

Corn (i.e. maize) starch brushed onto the lower half of the linen, then tested with hot templates,with first 4 imprinting starting left hand side, then with a further 3.

Only at the highest temperature was there what might be termed "starch assistance" comparable to that of white wheaten flour. However judging by poor imaging in a second impression, I suspect that what we are seeing here may be caramelization of starch, as distinct from a Maillard reaction, That's admittedly just a hunch, but is not something that can be readily explored further in a kitchen laboratory.

Might this simple technology have been used by a medieval artisan as the chemical basis for producing the image on the Turin Shroud? Answering that question may involve a great deal of further experimentation (on the TS as well as in model systems), but as the man said: "The longest journey begins with a single step".

Next question: how easy or how difficult is it to adapt the above technology for producing a negative imprint on linen (recalling that the TS image shows light/dark reversal as first shown by Secondo Pia in 1898)? Does the linen itself have to be pre-coated, or can one attach the flour directly to a template? The latter note does NOT have to be heated. Maybe the coated linen can be heated after imprinting first with flour. I shall continue for now to deploy a metal template (unheated), but note that there is no longer any reason for using metal. Any object with  a modicum of 3D surface relief could be used to leave its negative imprint on linen, at least in principle - including, dare one suggest, a cooperative human volunteer, as in those magnificent Garlaschelli studies.

To keep things simple (initially) a  shallow bas relief  horse brass was deployed in the next experiment (but one could imagine it being a live human being as well, assuming he or she were willing to submit to the messy  but otherwise low-biohazard procedure about to be described).

Before going on to describe that, a question that may be in folks' minds is "How firmly is that 'toasted flour' attached to the cloth? All I can say for now is that some test strips were placed in (a) tap water and (b) soapy water overnight, and had not noticeably dissolved in either liquid.

"Very firmly attached" would seem to be the answer for now.

Bas relief experiment
All ready to go: brass template, olive oil, and a sealable polythene bag with plain white flour. First smear a thin film of oil onto the template, then place inside bag, then, gripping the edges of template with fingers (through the plastic) ensure it becomes evenly dusted with flour.

Flour-coated template, ready for first printing-by-contact

OK, not the most sophisticated way of heating the linen and its (faint) flour imprint, but I needed to have everything open for maintaining a second-by-second watch with camera ready.

This looks interesting...
Even more interesting! Shame about the grid (and I should maybe have knocked off that surplus flour).

It's been over-roasted, obviously, but I wanted to see the (near) complete course in the initial run  short of total incineration. (Subtlety can wait till later). If you look carefully, you can even see the template lettering. Shame it's reversed, as happens with contact printing. Let's try flipping that imprint to see if one will be able to read GEORGE VI (left) and CORONATION 1937 (right and underneath)

Well, it's clearly lettering one can see inside the yellow box, though whether one can read all or part of "CORONATION" is another matter.  These are early days: maybe it's a mistake to expect too much of a powder imprint, when there's been no actual contact between hot metal and cloth., merely a kind of "fingerprint" technique.
Aside: one could call this technology the "flour fingerprinting" technique, though it would be necessary to qualify that by saying it's "thermally-assisted", to distinguish it from the dusting procedure used by detectives to detect real fingerprints.

That leaves the last of yesterday's experiments to be more fully documented - the attempt to imprint off a fully-3D template - one I have used previously in a direct thermal imprinting. Here's a reminder from that paper.

Direct thermal imprint, aka contact scorch: dorsal side of brass crucifix.

Here we go again: the new flour-imprinted crucifix experiment
The crucifix has been lightly oiled and placed inside the polythene bag with a little plain white flour.

Oops. I used too much oil. That's the flour/oil imprint underneath, and the crucifix after imprinting on top. The old towel was used to press the crucifix into the linen, with  several layers of  cloth underneath,  Never mind. Press on (regardless). This is a warts 'n' all presentation.


Here we see the first signs of yellowing, which are on the bearded chin and the chest. (The picture jumped up the page when I tried to attach a caption, so we'll enter "captions" as text for now, and try again later).

At this point, while an image of sorts was taking shape, it became clear that the temperature was rising to fast (the linen was sitting on an upturned oven tray placed over a hot ring). The next picture confirmed that impression.

Oh dear. Could do better. Like using gentle heat, over a longer period of time. Notice to fellow blogmeisters. Please do not display this photo as representative of the new technique. The only reason for displaying it now is archival: it  shows what can go wrong when one's in a hurry, using a modern electric hob with excessive rate of temperature rise. What's needed now is use of an oven with more stable temperature environment, albeit less handy for keeping tabs on progress and taking photographs.

OK, that's all the pictures (just a representative selection of some 120 taken yesterday).

So what's next?

Better more precise control of temperatrure, obviously. I shall be putting linen and flour separately in a domestic oven that came supplied with my kitchen laboratory, fitted with a detachable oven thermometer, a recent purchase, and then proceed  to establish the range of temperature that gives best differentiation between the coloration of flour and that of linen. It should hopefully then be possible to set the oven at an optimum temperature that allows development of the melanoidins of flour, i.e. Maillard reaction products, to be achieved by varying time rather than temperature.

There will then need to be microscopic examination of the linen fibres to establish the degree of superficiality of coloration.That has never been a road block in my conventional scorching experiments, contrary to claims that contact scorches affect all the fibres in a thread. I have shown that to be a complete fiction. Even intense scorches can affect only a relatively small number of fibres in the immediate vicinity of the contact zone. I may or may not find that to be the case also for the flour-sensitized system.

Reverse side scorching? There seems to be little of that, but some photographic evidence willbe sought.

Fluorescence? The fluorescence of conventional contact scorches has been a major factor in turning Hugh Farey, the BSTS Editor, against the scorch hypothesis. Maybe he could find time to check out a melanoidin-type scorch. I have no information to hand on whether they do or do not fluoresce. It would be a bit of a coup to have discovered a non-fluorescent scorch, n'est-ce-pas? Are you  busy this weekend, Hugh? Isn't it half term week coming up?

So much to do? How come no one else is doing these kinds of experiments, while Shroudie congresses come and go, with experts expatiating on the subtle characteristics of the TS image. Subtle in relation to what? Subtlety has no meaning if there are no model reference systems. Any reference system, even a classical contact scorch that is huffily ruled out of contention (why??) has surely to be better than no model at all.

Update Saturday pm

Have just used a fan oven set at 240 degrees Celsius and obtained this result with the new 'flour fingerprint' technology.

It's an acceptable image in gross terms, would you not agree? There's just one snag. It was powdery and easily brushed off. So there's a difference between roasting over a hot plate and roasting in a fan oven. Why that should be is something that is not immediately obvious. Or maybe there was some other difference, e.g. in amount of vegetable oil. Either way, it's good to see an image which (though I say it myself) might be said to occupy the Goldilocks zone (neither too sharp, nor too fuzzy). There is still so much to do. Maybe I should advertise for a lab technician, one who is prepared to evacuate the 'laboratory' whenever the General Manageress makes her entrance some 3 times per day.

PS:  It was even possible to get a second imprint off the same horse brass without needing to recoat with oil and flour, though the quality was needless to say somewhat inferior (and still brushed off).

It's only mentioned here since it demonstrates what might be termed the robustness of the imprinting technology.

Sunday 26 October

I shall concentrate for now on imprinting off the bas relief horse brass. The crucifix is problematical, mainly because of the way the arms lie in a different plane that makes it tricky to imprint equally all over. It's also wasteful on my dwindling reserves of pure linen.

What to do next?  It's probably worth a separate posting to flag up a handy feature of the flour-assisted technology. It can be used in either of two different ways.

Mode 1 (hot template): the linen can be dusted with flour, and the heated template then impressed, as in my feasibility experiment with the pencil sharpeners.

Mode 2 (cold template): as with the crucifix/horse brass experiments, the geometry can be reversed, with an unheated flour-coated template being pressed into linen, followed by a gentle roasting of the entire linen.

(Aside: did they perhaps have hot smoothing irons in medieval times? If so, it is possible to conceive of local 'ironing'  of  the flour-imprinted areas to allow selective browning where it's most needed, unless a conscious decision had been made to include an oven-roasting as per Garlaschelli to impart an aged look to the linen thereby "killing  two  birds with one stone".)

I'll try doing the two modes of imprinting in parallel  and then attempt to compare methodologies and outcomes with a view to deciding which ticks the most boxes.

The way the heating is done is crucial. In the Mode 2 'cold-template' procedure, I'll place flour-imprinted linen on top of a steel oven tray of high thermal capacity placed directly over a modern substitute for hot charcoal (a halogen ring) and then try raising the temperature slowly over several minutes, removing from heat if necessary, and maybe re-heating later. Temperature control is of the essence.

Sunday pm

OK, I've done my experimenting for the day, and released the lab facilities for Essential Back-Up Services.

The results show promise, but fall well short of being conclusive. Indeed, they could be said to add additional layers of complexity, especially if a mix of flour AND oil was used for imprinting. But then the TS image is complex and subtle*, as we are constantly reminded, so forgive me if I don't make apologies for discovering that an entire new range of options exists in modelling a facsimile of the TS image.

 * Afterthought: just because an image seems complex and subtle - especially when viewed centuries after its formation - does not mean that the technology that produced it was complex and subtle. A rainbow-coloured oil film on a waterway may look complex and subtle, but can be produced simply by releasing a little oil on the surface.

The more options the merrier, one might say, if only to counter those who taunt or deride science and scientists for "failing" to model the TS image, far less reproduce it in all its subtleties.  In passing, don't you just love the suggestion  that teams of scientists are labouring away day and night as we speak in a desperate attempt to disprove the Shroud's authenticity. Oh dear. Some folk simply do not understand the scientific temperament, which is curiosity (not agenda-) driven.

So I'm minded now to write up my morning's findings, warts 'n all, if only to demonstrate that the course of true science, like that of love, never did run smooth.

There's also the tiny detail that this blogger has never been strong in the personal-archiving department, i.e. the storing and organizing for ease of access of one's findings in a series of numbered files to be accessed weeks or months later when "writing up".

The great thing about the internet and blogosphere is that one's daily progress/setback report saves one having to do that. One just has to hope that Armageddon with a www-deleting electromagnetic pulse does not instantly destroy that internet archive. That would really spoil one's day.